Network management apparatus and method of selecting base station for software update

ABSTRACT

A network management apparatus inputs a plurality of work dates and time periods to update software in a base station. The apparatus obtains an n-week average of the numbers of connection calls during each of the input time periods for each day of the week, based on statistical information about connection with a wireless terminal in each base station. The apparatus obtains an m-month average of the numbers of connection calls during each of the input time periods for each date, based on the statistical information. The apparatus calculates, for each of the time periods for a work date, an average or a weighted average of the n-week average and the m-month average to obtain a degree of impact upon a communication service. A processing section selects a work date and a time period having the minimum degree of impact and updates the software.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation application of applicationSer. No. 11/483,775, filed Jul. 11, 2006; which is acontinuation-in-part application of application Ser. No. 10/636,806,filed Aug. 8, 2003, the subject matter of which is incorporated byreference herein. Applicants hereby claim the right of priority based onJapanese Patent Application No. 2005-202799, filed in Japan on Jul. 12,2005 and in Japanese Patent Application Nos. 2003-117281, filed in Japanon Apr. 22, 2003 and 2003-157584, filed in Japan on Jun. 3, 2003, thesubject matter of which is also incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to network management apparatuses andmethods of selecting a base station for software update. In particular,the present invention relates to a network management apparatus and amethod of selecting a base station for software update for carrying outsoftware update in a wireless communication system base station.

In typical conventional communication networks, it is important toensure reliability to prevent interruption of communication. For thisreason, software for providing communication services and controllingthe operation of communication networks should be preferably updatedwithout having to stop communication services. For example, a method ofupdating software in a system in which hardware is redundantlyconfigured so that software installed in non-operating hardware isupdated is disclosed in Japanese Unexamined Patent ApplicationPublication No. Hei-7-319683 and No. 2001-56759.

On the other hand, wireless communication networks allow each basestation to communicate with each wireless terminal within an area calleda “cell”, which is a coverage area of radio waves from the base station.Typical cells have a radius of several kilometers. Thus, typicalwireless communication networks are characterized in that they canaccommodate only a smaller number of users with a smaller coverage area,compared with known wired communication networks (exchange networks). Toovercome this disadvantage, in a typical wireless communication network,a large number of such base stations need to be arranged to providecommunication services over a wide area. For this reason, if such manybase stations are redundantly configured in the same manner as the wiredcommunication network facility described in the Japanese UnexaminedPatent Application Publication No. Hei-7-319683 and No. 2001-56759, theeconomical efficiency of communication networks is significantlyimpaired. In addition, in that case, a plurality of frequency bands andCDMA spread codes need to be assigned, which leads to waste of limitedresources and decreases the number of users resulting in declining thecapability of providing users with services. As a solution to thisdrawback, a method of updating software installed in a base stationwhile communication services of the base station are suspended during acertain time period, such as midnight, is disclosed in JapaneseUnexamined Patent Application Publication No. Hei-10-63498.

Furthermore, in CDMA wireless communication networks, a technique forupdating software while uninterruptedly switching a communication pathfrom the current wireless base station to another wireless base stationor to a sector through the use of soft handover technology andelectrical power control technology is described in Japanese UnexaminedPatent Application Publication No. 2005-10821.

SUMMARY OF THE INVENTION

Unfortunately, from the perspective of an entire wireless communicationnetwork, all the above-described methods in which hardware does not havea redundant structure force limited operation, in which the number ofusers who can receive communication services at the same time is reducedsignificantly or slightly, during software updating. Therefore, ofwireless base stations that do not have hardware of redundant structure,a base station with less traffic should be preferably selected forsoftware update work.

However, the task of selecting a base station with less traffic is noteasy because a wireless communication network includes many wirelessbase stations and furthermore, traffic characteristics (for example, theamount of traffic and periods at which traffic increases and decreases)processed by these base stations greatly differ depending on thecoverage area, day of the week, date, and time period. For example,traffic will increase at night on weekends in downtown areas, whiletraffic will increase during the daytime, weekdays, in businessdistricts. It is also probable that traffic will increase at the end ofmonth, such as on a payday and several days after the payday.Furthermore, the average number of users who use communication servicesby wireless base stations will greatly differ between sparsely populatedareas and urban areas. From these considerations, a known method inwhich a wireless base station with a possibly small number of usersreceiving communication services, for example, at midnight is selectedfor software update is problematic because the number of users usingcommunication services at midnight may not be small in downtown areas,and therefore, software update is difficult at midnight for wirelessbase stations located in downtown areas.

In order to maximize the communication service in the entire wirelesscommunication network, it is preferable that software update in adowntown area be carried out during a time period on a date and a day ofthe week with the minimum traffic in the downtown area, and similarly,software update in a mountain area be carried out during a time periodon a date and a day of the week with the minimum traffic in the mountainarea. In short, methods of selecting a wireless base station with aminimum number of users who receive communication services during acertain time period are not always satisfactory. Instead, methods ofselecting a date, day of the week, and time period with a minimum numberof users who receive communication services in a certain area are morepreferable.

In light of these circumstances, an object of the present invention isto provide a wireless-base-station selection method for updatingsoftware installed in a wireless base station at a date, day of theweek, and time period corresponding to the minimum number of users whoreceive communication services by the wireless base station covering acertain area. Another object of the present invention is to minimize theinfluence of software update on communication services provided forusers.

One of methods for selecting the date, day of the week, and time periodhaving the minimum number of users who are receiving communicationservices in a certain area is to refer to statistical information of thepast. In a wireless communication network, many of the areas covered bywireless base stations overlap the areas covered by adjacent basestations. For this reason, even if a certain base station suspendscommunication services, some of the terminals receiving thecommunication services by that wireless base station may be able tocontinuously receive the communication services by an adjacent wirelessbase station. Thus, software update should preferably not be carried outfor a certain wireless base station and wireless base stations adjacentthereto at the same time. As described above, due particularly to a hugenumber of used wireless base stations, it is not easy to select awireless base station, date, day of the week, and time period having theminimum number of users by taking into consideration both time-seriesstatistical information and geographical conditions of adjacent wirelessbase stations.

In order to achieve the above-described objects, the present inventionfocuses attention on the fact that traffic characteristics exhibit acertain regularity with respect to the area, date, day of the week, andtime period, as described above. Based on this fact, in the presentinvention, a network management apparatus acquires statisticalinformation from wireless base stations and classifies the acquiredinformation by wireless base station, day of the week, date, and timeperiod and holds it. Based on the retained statistical information,software-update-work information (span of time, time period in a day)from a maintenance operator, and information about adjacent wirelessbase stations, the date, day of the week, and time period having theminimum number of users who are receiving communication services by awireless base station are acquired and then reported to the networkmanagement apparatus (or the maintenance person). Furthermore, by usingthe result of acquisition, the network management apparatus carries outsoftware update autonomously.

A wireless base station according to the present invention is, forexample, a wireless base station for performing communication between awireless terminal and a wired communication network in a wirelesscommunication network. It includes a wireless interface forcommunication with the wireless terminal; a wired interface forcommunication with the wired communication network; a communicationprocessing section for performing processing to provide the wirelessterminal with a communication service via the wireless interface and thewired interface; and a control section for controlling an apparatus. Thecontrol section updates installed software to software received via thewired interface.

A wireless communication network according to the present inventionincludes, for example, a wireless base station for performingcommunication between a wireless terminal and a wired communicationnetwork; a control apparatus for communicating with the wireless basestation; and a network management apparatus for managing the wirelesscommunication network. The wireless base station or the controlapparatus reports statistical information about traffic to the networkmanagement apparatus. The network management apparatus selects a dateand time for software update in a wireless base station using apredetermined rule based on the statistical information about trafficreported from the wireless base station or the control apparatus andsoftware-update-work resource information from a maintenance person (thenumber of base stations where software update can be performedsimultaneously, span of time, and time period in a day) and reports themto the maintenance person. The network management apparatus thentransmits update software and an update request to the selected wirelessbase station at the selected date and time. The wireless base stationreceives the software and the update request transmitted from thenetwork management apparatus and updates the installed software to thereceived software according to the received update request.

In another aspect, for example, a wireless communication networkincludes a wireless base station for performing communication between awireless terminal and a wired communication network; a control apparatusfor performing communication with the wireless base station; and anetwork management apparatus for managing the wireless communicationnetwork. The network management apparatus determines a software-updatedate and time for the wireless base station based on a predeterminedrule from a work plan sent from a maintenance person, statisticalinformation about the wireless base station, and information about anadjacent wireless base station and reports the determined date and timeto the maintenance person. It then transmits update software and anupdate request to the wireless base station at the determined date andtime. The wireless base station receives the software and the updaterequest transmitted from the network management apparatus and updatesthe installed software to the received software according to thereceived update request.

Each of the above-described network management apparatuses includes, forexample, a memory for storing a neighbor identifier for identifying awireless base station adjacent to the wireless base station concerned inassociation with an apparatus identifier for identifying the wirelessbase station concerned. The network management apparatus refers to thememory to identify a wireless base station adjacent to the selectedwireless base station so as not to select the adjacent wireless basestation for software update performed at the same date and time.

Each of the above-described network management apparatuses includes, forexample, a memory for storing the number of call connections occurringin the past in the wireless base station concerned in association withan apparatus identifier for identifying the wireless base stationconcerned. The network management apparatus refers to the memory andanalyzes the number of call connections based on a predetermined rulefor each day of the week and time period and each date and time period.

Each of the above-described network management apparatuses includes, forexample, a memory for storing the result of analysis of the number ofcall connections of the past in the wireless base station concerned, foreach day of the week and time period and each date and time period,based on a predetermined rule; and a neighbor identifier for identifyinga wireless base station adjacent to the wireless base station concernedin association with an apparatus identifier for identifying the wirelessbase station concerned. The network management apparatus refers to thememory to select a wireless base station and a software-update date andtime where the result of analysis of the number of call connections ofthe past in the wireless base station for each day of the week and timeperiod and each date and time period based on a predetermined ruleexhibits the minimum number of processed calls, provided that a wirelessbase station adjacent to the wireless base station concerned is notselected for software update performed at the same date and time.

Each of the above-described network management apparatuses reports, forexample, the selected wireless base station and software-update date andtime to the maintenance person before the transmission of a softwareupdate request.

A method of selecting a wireless base station for software update in thewireless base station according to the present invention is, forexample, a method of selecting a wireless base station in a wirelesscommunication network that includes a wireless base station forperforming communication between a wireless terminal and a wiredcommunication network, a control apparatus for communicating with thewireless base station, and a network management apparatus for managingthe wireless communication network. This method includes the steps ofthe network management apparatus analyzing statistical information abouttraffic reported from the wireless base station or the control apparatusby classifying it for each wireless base station, day of the week, date,and time period; the network management apparatus selecting a date, dayof the week, and time period having the minimum number of users who arereceiving communication services by the wireless base station accordingto the statistical information analyzed based on software-update-workresource information (the number of base stations where software updatecan be performed simultaneously, span of time, time period in a day)from the maintenance person; the network management apparatus reportingthe selection result to the maintenance person as a software-updateplan; and the network management apparatus transmitting update softwareand an update request to the selected wireless base station on the date,day of the week, and time period selected according to the selectionresult.

According to the first solving means of this invention, there isprovided

a network management apparatus in a wireless communication network,which comprises a wireless base station for performing communicationbetween a wireless terminal and a wired communication network and, thenetwork management apparatus for managing a network, the networkmanagement apparatus comprising:

a storage section stored in advance number of calls of connection withthe wireless terminal in the wireless base station in association with adate, a day of the week, and a time period; and

a processing section for selecting a date and a time period whensoftware is updated in the wireless base station,

wherein the processing section

inputs a plurality of work dates and time periods when the software isupdated in the wireless base station,

obtains an n-week average of the numbers of connection calls occurringduring each input time period for each day of the week, based on thenumber of connection calls stored in the storage section, where n is apredetermined integer,

obtains an m-month average of the numbers of connection calls occurringduring each input time period for each stored date, based on the numberof connection calls stored in the storage section, where m is apredetermined integer,

calculates an average or a weighted average of the n-week averagecorresponding to each time period and the day of the week of each inputwork date and the m-month average corresponding to each time period andeach input work date to obtain a degree of impact representing an impactcaused by software update upon a communication service,

selects a work date and a time period with the minimum degree of impactor with a degree of impact equal to or smaller than a predeterminedthreshold, and

updates the software installed in the wireless base station during theselected time period on the selected work date.

According to the second solving means of this invention, there isprovided a method of selecting a wireless base station to updatesoftware installed in the wireless base station at a selected timeperiod on a selected date, the method comprising the steps of:

inputting a plurality of work dates and time periods when the softwareof the wireless base station is updated;

obtaining an n-week average of the numbers of connection calls occurringduring each of the input time periods for each day of the week, based onthe number of calls of connection with a wireless terminal in thewireless base station, corresponding to each date, day of the week, andtime period, where n is a predetermined integer;

obtaining an m-month average of the numbers of connection callsoccurring during each of the input time periods for each date, based onthe number of connection calls, where m is a predetermined integer;

calculating an average or a weighted average of the n-week averagecorresponding to each time period and the day of the week of each inputwork date and the m-month average corresponding to each time period andeach input work date to obtain a degree of impact representing an impactcaused by software update upon a communication service; and

selecting a work date and a time period having the minimum degree ofimpact.

According to the present invention, a method of selecting a date, day ofthe week, and time period having the minimum number of users who arereceiving communication services be a wireless base station can easilybe realized, and therefore, the influence of software update upon thecommunication services provided for users can be minimized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram depicting the structure and an exampleoperation of a wireless communication network.

FIG. 2 is a block diagram showing an example structure of a networkmanagement apparatus.

FIG. 3 is a diagram for describing an example software update operation.

FIG. 4 illustrates one example of a software-update-plan input screen.

FIGS. 5A and 5B illustrate example screens reporting software-updatebase-station and date-and-time selection-results.

FIG. 6 is a diagram showing an example of statistical informationanalysis for selecting a base station for software update.

FIG. 7 is a flowchart illustrating an example of statistical informationanalysis for each day of the week, for selecting a base station forsoftware update.

FIG. 8 illustrates one example of a result of the statisticalinformation analysis for each day of the week, for selecting a basestation for software update.

FIG. 9 is a flowchart illustrating an example of statistical informationanalysis for each date, for selecting a base station for softwareupdate.

FIG. 10 illustrates one example of a result of the statisticalinformation analysis for each date, for selecting a base station forsoftware update.

FIGS. 11A and 11B illustrate example results of integration of theday-of-the-week statistical information analysis and the date-basedstatistical information analysis, for selecting a base station forsoftware update.

FIG. 12 is a flowchart illustrating an example of selecting basestations and dates and times for software update.

FIG. 13 illustrates an example table of selecting base stations anddates and times for software update.

FIG. 14 illustrates a resultant table of selecting base stations anddates and times for software update.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The structures of wireless base stations and a wireless communicationnetwork and a method of selecting a wireless base station for softwareupdate among the wireless base stations according to an embodiment ofthe present invention will be described below with reference to thedrawings.

FIG. 1 is a block diagram depicting an example structure of a wirelesscommunication network to which this embodiment is applied. A wirelesscommunication network 10 has the following structure to allowcommunication between terminals.

A plurality of mobile terminals MS1 300-1 and MS2 300-2 are connected toa plurality of wireless communication apparatuses (hereinafter, referredto as base stations) BS1 110-1 to BS8 110-8 via wireless communicationpaths (not shown in the figure). More specifically, radio-wave coverageareas called cells 100-1 to 100-8 are defined for the base stations BS1to BS8 to allow wireless communication with terminals MS, for example,by using CDMA. In this embodiment, areas in which these base stationsBS1 110-1 to BS8 110-8 can communicate with terminals MS are called amobile communication network 400.

Each of the base stations BS1 110-1 to BS8 110-8 in a mobilecommunication network 400-1 is connected to a base-station controlsection (control apparatus) 200-1 via communication paths 500-1. Whenthe destination terminal of a call sent from the terminal MS1 300-1exists in the same mobile communication network 400-1, the base-stationcontrol section 200-1 returns the signal to one of the subordinate basestations BS1 110-1 to BS8 110-8 to communicate with the destinationterminal MS. On the other hand, when the destination terminal is locatedin another mobile communication network 400-2 (the structure thereof issimilar to that of the mobile communication network 400-1, and thus adescription thereof will be omitted here), the base-station controlsection 200-1 communicates with the destination terminal by using abase-station control section 200-2 and the mobile communication network400-2 to send and receive signals via a communication network 150connecting the base-station control sections 200. The communicationnetwork 150 can be realized by a public network, a leased line network,or a private network. In addition, the mobile communication network400-2 can be realized by a so-called fixed network including a wiredcommunication network and terminals stationarily connected thereto.

A network management apparatus 250 is connected to base stations BS 110and base-station control sections 200 provided for the communicationnetwork 10 via a control-signal communication paths 600 for transmittingand receiving control signals, such as monitoring and maintenancesignals, to manage and control the entire facility of the communicationnetwork 10. For example, the network management apparatus 250 selects abase station 110 for which software is to be updated and outputs asoftware-update instruction to the base station 110. The communicationnetwork 10 can include any appropriate numbers of base stations BS 110,base-station control sections 200, and network management apparatuses250. The numbers are not limited to those shown in FIG. 1.

FIG. 2 is a block diagram showing an example structure of the networkmanagement apparatus 250. The network management apparatus 250 has thefollowing structure and communicates with the base stations 110 or thebase-station control sections 200 via the control signal communicationpaths 600 to control these components.

The network management apparatus 250 manages maintenance and operationof the whole of the wireless communication network 10, including aplurality of mobile communication networks 400 each accommodating aplurality of base stations 110. More specifically, the networkmanagement apparatus 250 includes, for example, a plurality of input andoutput (I/O) interfaces 254, a CPU 251, a memory 252, a storage device253, an input section such as a keyboard 256, and a display section suchas a monitor 257, and these components are interconnected via aninternal bus 255.

The storage device 253 stores statistical information 1 such as thenumber of connection calls in a wireless base station. The memory 252stores tables used to select base stations for software update. Tablesstored in the memory 252 include, for example, a software update table2, a first schedule table 3, a second schedule table 4, a day-of-weekcall table 5, a daily call table 6, a service impact table 7, and aschedule adjustment table 8. Details of each table will be describedlater. The statistical information 1 may be stored in the memory 252 orinput from an external storage device.

Each I/O interface 254 functions as a communication interface with thebase stations 110 and the base-station control sections 200 provided forthe wireless communication network 10. The CPU 251 controls the entirenetwork management apparatus 250 to carry out maintenance operation ofthe entire mobile communication networks 400, including the basestations 110, by transmitting and receiving control signals (commandsand other information) and data via the I/O interfaces 254.

The memory 252 stores, for example, programs executed by the CPU 251.The storage device 253 stores data (for example, information aboutterminals and base stations) necessary for the network managementapparatus 250 to operate the wireless communication network 10 andsoftware and firmware which are to be updated at the base stations 110.The keyboard 256 is input means for inputting instructions, for example,by a maintenance person, and the monitor 257 is display means forreporting, for example, the operating state of the wirelesscommunication network 10 and software update information at the basestations 110 to the maintenance person. Appropriate means, apparatuses,and devices can be used as input means and output means.

The network management apparatus 250 periodically acquires information,such as the number of users receiving communication services, of eachbase station 110, from that base station 110 or the correspondingbase-station control section 200 and stores the information in thememory 252 or the storage device 253. Furthermore, the networkmanagement apparatus 250 stores in the storage device 253 software andfirmware to be updated, according to an instruction from, for example,the maintenance person and then assists in the selection of a date, aday of the week, and a time period for software update in the basestation 110 and actual software update at the base station 110 accordingto the procedure described below.

FIG. 3 is a sequence diagram showing a workflow associated with softwareupdate in each base station 110 according to this embodiment. Themaintenance person carries out software-update-plan inputting (in step3-1) into the network management apparatus 250. For example, the networkmanagement apparatus 250 inputs a software-update plan via the keyboardoperated by the maintenance person. The plan includes a “software-updatestart date,” a “software-update end date,” a “work time period,” and a“base station to be scheduled.” Software-update work dates aredetermined with the input “software-update start date” and“software-update end date.” Alternatively, software-update work datesmay be specified by appropriate means. For example, they may be inputdirectly, or they may be selected non-consecutively.

FIG. 4 shows an example input screen displayed on the monitor 257 of thenetwork management apparatus 250 in a process of software-update-planinputting (in step 3-1). Various items of information are input on thisscreen. In order to specify a “base station to be scheduled,” aselection button may be pressed to make reference to the software updatetable 2 to display various items of information including “base-stationnumbers,” “station names,” “software version numbers,” and “applied/notapplied”, as shown in FIG. 4, so that the maintenance person can selectwhether scheduling of each base station is “applied” or “not applied.”

When the selected software-update plan is input, the network managementapparatus 250 carries out a statistical-information analysis process (instep 3-2) and then carries out a software-update base-station anddate-and-time selection process (in step 3-3). Each of the processes (insteps 3-2 and 3-3) will be described later in detail. In addition, thenetwork management apparatus 250 carries out selection result reporting(in step 3-4) to the maintenance person. Selection result reporting ismade to the maintenance person by displaying on the monitor 257 a dailysoftware update schedule and scheduled dates of software update in theform of a list of base stations.

FIGS. 5A and 5B show example screens of selection result reporting. Inthe current description, a table that includes “scheduled date,”“base-station number,” “station name,” “software version number,”“approved/not approved,” and “date of notification,” which is displayedon a “software-update base-station and date-and-time selection-resultreport screen 1” of FIG. 5A, is referred to as the first schedule table3. Furthermore, in the current description, a table that includes“base-station number,” “station name,” “software version number,”“applied/not applied,” “scheduled date,” “approved/not approved,” and“date of notification,” which is displayed on a “software-updatebase-station and date-and-time selection-result report screen 2” of FIG.5B, is referred to as the second schedule table 4. It is acceptable toreport and display only one of the schedule tables or to report anddisplay both the schedule tables. The maintenance person checks the basestations and dates and times for software update, and when the reportedschedule is acceptable, carries out selection result approval (in step3-5). For example, the network management apparatus 250 inputs apredetermined item of information and a signal indicating approval viainput means such as the keyboard 256. The selection result approval (instep 3-5) can be carried out for one base station, a plurality of basestations simultaneously, or all base stations to be scheduled,simultaneously. On the other hand, if the selection result is notacceptable because, for example, base-station works conflicting with areported software update schedule have been determined suddenly, it ispossible not to approve the selection result for the adversely affectedbase stations 110, the approval of the adversely affected base stations110 can be canceled, or the schedule can be modified at thesoftware-update-plan inputting (in step 3-1). In this case, the basestations for which the selection result is not approved or for which theapproval of the selection result is canceled can be excluded from thecandidates before starting again the process (in step 3-1) and thesubsequent processes.

Based on the above-described selection result, a software updateinstruction is issued (in step 3-6) by the network management apparatus250 to the base stations 110 whose selection results have been approvedwith respect to the selected dates and times. When each of the relevantbase stations 110 receives the issued software update instruction, itcarries out software update (in step 3-7). The software update (in step3-7) in the base station 110 can be carried out while communicationservices are stopped, as described in Japanese UnexaminedPatentApplication Publication No. Hei-10-63498, or while thecommunication services are switched therefrom to another base station110, as described in Japanese Unexamined Patent Application PublicationNo. 2005-10821. Other methods can also be used. When the software updateis completed (in step 3-7), the base station 110 transmits a softwareupdate completion report to the network management apparatus 250 (instep 3-8). In response, the network management apparatus 250 carries outsoftware-update-result-information update (in step 3-9). For example,the network management apparatus 250 records the date when the softwareupdate completion report was received (date of notification) in thefirst schedule table 3 and the second schedule table 4 in associationwith the base-station number of the base station from which the softwareupdate completion report was received. Software update completion by thebase station 110 is reported to the maintenance person as shown, forexample, in “date of notification” of FIG. 5.

Next, the statistical-information analysis process (in step 3-2) in FIG.3 will be described in detail. Based on the fact that user traffic iscorrelated with information such as the coverage area of the basestation 110, date, day of the week, and time period, the networkmanagement apparatus 250 classifies statistical information acquired inthe past, such as the number of users who receive communication services(hereinafter, referred to as the number of connection calls), by date,day of the week, and time period for each base station 110 planned forsoftware update to analyze the statistical information. A specificmethod for carrying out this analysis is described with reference toFIGS. 6 to 10.

FIG. 6 is a diagram depicting a flow of the statistical-informationanalysis process (in step 3-2). First, the network management apparatus250 carries out a day-of-the-week statistical process (in step 6-1),which is a process of arranging statistical information of the past bythe day of the week. Thereafter, the network management apparatus 250carries out a date-based statistical process (in step 6-2), which is aprocess of arranging statistical information of the past by the date,and then integrates day-of-the-week and date-based statistical processresults (in step 6-3).

FIG. 7 shows a flowchart of the day-of-the-week statistical process (instep 6-1). It is noted that information in the past n weeks (n is apredetermined integer) can be used for statistical information used inthe day-of-the-week statistical process (in step 6-1). FIG. 8 shows theday-of-week call table 5, which contains the result of a day-of-the-weekstatistical process performed for a certain base station according tothe flow shown in FIG. 7. Although the averages of the numbers ofconnection calls from one to n weeks ago are indicated by integers inFIG. 8, they can be indicated by decimals. The day-of-week call table 5may be provided for each base station to be scheduled.

In the day-of-the-week statistical process (in step 6-1), the networkmanagement apparatus 250 carries out a process of “reading fromstatistical information stored in the storage device 253 the number ofconnection calls occurring in a certain base station during a timeperiod “k” on a day of the week “j”, “i” weeks ago” (in step 7-1), where“i” is a value from one to n, “j” is identification informationindicating Monday through Saturday and Sunday (holidays may beincluded), and “k” is identification information indicating a work timeperiod specified by the maintenance person (each of three time periods“10:00-12:00,” “13:00-15:00,” and “15:30-17:30” in the case of FIG. 4).The number of connection calls stored as statistical information in thestorage device 253 of the network management apparatus 250 isperiodically acquired at certain time intervals; for example, the numberof connection calls is stored every five minutes. For this reason, thenumber of connection calls during a time period k can be stored in theform of a sequence including a plurality of terms. If it is assumed thatthe number of connection calls is stored in the network managementapparatus 250, for example, every five minutes, the numbers ofconnection calls during the time period 10:00-12:00 are expressed as asequence of 24 terms each indicating the number of connection calls,such as a sequence of 24 terms “10, 7, 5, 6, 8, 9, 11, 9, 5, 7, 10, 9,8, 6, 9, 9, 10, 8, 12, 8, 7, 5, 9, 9.” Such a sequence is stored in thestorage device 253 in association with, for example, a certain date, dayof the week, and time period. The sequences may be not stored inassociation with the day of the week. In that case, reference is made toan appropriate calendar in the apparatus to obtain the day of the weekcorresponding to each date. Alternatively, the average of the numbers ofconnection calls over every predetermined period, such as from 10:00 to12:00, may be stored.

The network management apparatus 250 carries out a process of averagingthese sequences by a unit time (hour or minute) by performing a processof “obtaining, from the read numbers of connection calls, the average ofthe numbers of connection calls per unit of time that occurred in acertain base station during a time period “k” on a day of the week “j”,“i” weeks ago” (in step 7-2). For example, the numbers of connectioncalls (for example, 24) which have been read from the data correspondingto a day of the week “j”, “i” weeks ago are averaged, and the averagednumber of connection calls is then stored in the day-of-week call table5 such that it is associated with the corresponding week, day of theweek, and time period. The network management apparatus 250 performs aprocess of “repeating the above-described processes (in steps 7-1 and7-2) for i=[one to n weeks]” (in step 7-3) to obtain the average of thenumbers of connection calls occurring in a certain base station during atime period “k” on a day of the week “j” for each week from one to nweeks ago.

Next, the network management apparatus 250 obtains an “n-week average”(as defined below) for a day of the week “j” and a time period “k” in acertain base station by carrying out a process of “obtaining the averageof the averages of the numbers of connection calls per unit of time,during a time period “k” on a day of the week “j”, over the period fromone to n weeks ago (referred to as the “n-week average”)” (in step 7-4).In addition, the obtained n-week average is stored in the day-of-weekcall table 5 such that it is associated with the corresponding day ofthe week and time period. The network management apparatus 250 obtainsthe “n-week average” in a certain base station for all time periods onall days of the week by carrying out a process of “repeating theabove-described processes (in steps 7-1 to 7-4) for “j”=[Monday throughSaturday and Sunday (holidays may be included)] and “k”=[work timeperiods specified by the maintenance person]” (in step 7-5).Furthermore, the network management apparatus 250 obtains the “n-weekaverage” for all days of the-week and all time periods in all basestations to be scheduled by carrying out a process of “applying theabove-described processes (in steps 7-1 to 7-5) to all the base stationsto be scheduled” (in step 7-6).

FIG. 9 shows a flowchart for the date-based statistical process (in step6-2). It is noted that information in the past m months (m is apredetermined integer) can be used for statistical information used inthe date-based statistical process (in step 6-2). FIG. 10 shows thedaily call table 6, which contains the result of a date-basedstatistical process performed according to the flow shown in FIG. 9.Although each average of the numbers of connection calls and eachm-month average are indicated by integers in FIG. 10, they may beindicated by decimals. One daily call table 6 may be provided for eachbase station to be scheduled.

In the date-based statistical process (in step 6-2), the networkmanagement apparatus 250 carries out the process of “reading the numberof connection calls occurring in a certain base station, during a timeperiod “k” on a date “d”, “p” months ago” (in step 9-1), where “p” is avalue from one to m, “d” is a value from 1 to 31, and “k” isidentification information indicating a work time period specified bythe maintenance person (each of three time periods “10:00-12:00,”“13:00-15:00,” and “15:30-17:30” in the case of FIG. 4). The number ofconnection calls stored as statistical information in the networkmanagement apparatus 250 is periodically acquired at certain timeintervals as described above; for example, the number of connectioncalls is stored every five minutes. For this reason, the number ofconnection calls during a time period “k” can be stored in the form of asequence including a plurality of terms. If it is assumed that thenumber of connection calls is stored in the network management apparatus250, for example, every five minutes, the numbers of connection callsduring the time period 10:00-12:00 are expressed as a sequence of 24terms each indicating the number of connection calls. The networkmanagement apparatus 250 carries out a process of averaging thesesequences by a unit time (hour or minute) by performing a process of“obtaining, from the read numbers of connection calls, the average ofthe numbers of connection calls per unit of time that occurred in acertain base station during a time period “k” on a date “d”, “p” monthsago” (in step 9-2). For example, the numbers of connection calls whichhave been read through the process (in step 9-1) are averaged, and theaverage of the numbers of connection calls is then stored in the dailycall table 6 such that it is associated with the corresponding month,date, and time period. The network management apparatus 250 performs aprocess of “repeating the above-described processes (in steps 9-1 and9-2) for “p”=[one to m months]” (in step 9-3) to obtain the average ofthe numbers of connection calls occurring in a certain base stationduring a time period “k” on a date “d” for each month from one to mmonths ago.

Next, the network management apparatus 250 obtains an “m-month average”(as defined below) for a date d and a time period k in a certain basestation by carrying out a process of “obtaining the average of theaverage of the numbers of connection calls per unit of time during atime period “k” on a date “d”, over the period from one to m months ago(referred to as the “m-month average”)” (in step 9-4). In addition, thenetwork management apparatus 250 stores the obtained m-month average inthe daily call table 6 such that it is associated with the correspondingdate and time period. The network management apparatus 250 obtains the“m-month average” in a certain base station for all time periods on alldates by carrying out a process of “repeating the above-describedprocesses (in steps 9-1 to 9-4) for “d”=1 to 31 and “k”=[each work timeperiod specified by the maintenance person]” (in step 9-5). Furthermore,the network management apparatus 250 obtains the “m-month average” forall the dates and all the time periods in all the base stations to bescheduled by carrying out a process of “applying the above-describedprocesses (in steps 9-1 to 9-5) to all the base stations to bescheduled” (in step 9-6).

Next, in the “process of integrating day-of-the-week and date-basedstatistical process results” (in step 6-3) of FIG. 6, the “n-weekaverage” stored in the day-of-week call table 5 of FIG. 8 and the“m-month average” stored in the daily call table 6 of FIG. 10 areintegrated for each base station by weighting them by the respectivenumbers of samples (by obtaining the weighted average). In this manner,the influence upon communication services for users (hereinafter,referred to as the degree of impact) is represented in a numerical form,classified by date, day of the week, time period. More specifically, thenetwork management apparatus 250 calculates the degree of impact by thefollowing expression:

Degree of impact={(n×[n-week average])+(m×[m-month average])}/(n+m)

For example, the degree of impact is calculated for each base station,each input work date, and each time period. Furthermore, the networkmanagement apparatus 250 stores the obtained degree of impact in theservice impact table 7 such that it is associated with the correspondingdate, day of the week, and time period. The day of the week can beobtained based on the date by referring to an appropriate calendarinside or outside the apparatus.

For example, if software update is planned at “10:00-12:00 on the secondday, Monday,” the influence upon communication services for users at“10:00-12:00 on the second day, Monday” is calculated as (1.5n+3m)/(n+m)because the “n-week average” at 10:00-12:00 on Monday is “1.5” accordingto FIG. 8 and the “m-month average” at 10:00-12:00 on the second day is“3” according to FIG. 10. The network management apparatus 250calculates the influence on communication services in a numerical formfor all time periods and all dates from the software-update start dateto the end date.

FIGS. 11A and 11B show examples of the service impact table 7. Theservice impact table 7 stores the degree of impact upon communicationservices for users in each base station, classified according to date,day of the week, and time period. In the examples of FIGS. 11A and 11B,the lowest influence upon communication services for users is seen at10:00 to 12:00 on September 2 (Monday) (degree of impact is 1.6) forbase-station number 1 and is seen at 13:00 to 15:00 on September 2(Monday) (the degree of impact is 9.4) for base-station number 2.

In the “process of integrating day-of-the-week and date-basedstatistical process results” (in step 6-3), the influence uponcommunication services for users can be expressed in a numerical form,classified by date, day of the week, and time period, with an emphasisplaced upon either day of the week or date, by multiplying the day ofthe week and the date by predetermined weights “a” and “b”,respectively, (obtaining the weighted average) based on the expressionbelow.

{(a×n×[n-week average])+(b×m×[m-month average])}/(n+m)

Next, the software-update base-station and date-and-time selectionprocess (in step 3-3) in FIG. 3 will be described. In the wirelesscommunication network 10, many of the coverage areas of the basestations 110 overlap with those of adjacent base stations. Therefore,even if a certain base station 110 stops communication services, some ofthe terminals 300 receiving communication services from that basestation 110 can receive the communication services from an adjacent basestation in some cases. For this reason, the chance of interruptingcommunication services can be reduced by avoiding carrying out softwareupdate in a certain base station and base stations adjacent theretosimultaneously. In the software-update base-station and date-and-timeselection process (in step 3-3), a base station, a date, a day of theweek, and a time period for software update are selected based on thedegree of impact upon communication services for users obtained throughthe statistical-information analysis process (in step 3-2) andpredetermined information about adjacent base stations.

FIG. 12 shows a specific processing flow of the software-updatebase-station and date-and-time selection process (in step 3-3). FIG. 13shows an example structure of the schedule adjustment table 8. Theschedule adjustment table 8 includes, for example, “base-stationnumber,” “degree of impact upon communication services for users,”“adjacent base-station number,” “software update schedule,” and“tentative determination/determination.”

In FIG. 12, the network management apparatus 250 performs a process of“making a tentative determination of the date, the day of the week, andthe time period corresponding to the minimum degree of impact uponcommunication services for users for all base stations to be scheduled”selected on the base-station-to-be-scheduled selection screen shown inFIG. 4 (in step 12-1). In this process, the network management apparatus250 refers to the service impact table 7 shown in FIGS. 11A and 11B toselect the date, the day of the week, and the time period having theminimum degree of impact upon communication services for users in eachbase station. The network management apparatus 250 specifies theselected date, day of the week, and time period as a “software updateschedule” in the schedule adjustment table 8. Furthermore, the degree ofimpact upon communication services for users, corresponding to theselected date, day of the week, time period is set, and “tentativedetermination” is set in the “tentative determination/determination”field.

Next, with respect to a certain base station A to be scheduled forsoftware update, a process of “determining whether there is a basestation B adjacent to the base station A and having the same softwareupdate date, day of the week, and time period as the tentativelydetermined date, day of the week, and time period” is performed (in step12-2). For example, the network management apparatus 250 refers to theschedule adjustment table 8 to acquire the base-station numbers (forexample, 1, 3, 7, 8 . . . ) of the base stations adjacent to the basestation corresponding to the base-station number to which the process isapplied (for example, base-station number 2). Thereafter, the networkmanagement apparatus 250 searches the schedule adjustment table 8 forthe acquired adjacent base-station numbers and reads the software updateschedule corresponding to each of the acquired base-station numbers. Thenetwork management apparatus 250 determines whether the software updateschedule (for example, at 13:00-15:00 on September 2 (Monday)) of thebase-station number to which the process is applied (for example,base-station number 2) conflicts with the time period of the acquiredsoftware update schedule.

In the case of FIG. 13, the time period of the software update schedulefor base-station number 1 does not conflict with any of the time periodsof the software update schedules for base-station numbers 2, 3, 4, 6,and 7, which are the numbers of base stations adjacent to the basestation with base-station number 1. Therefore, the determination resultin the process (in step 12-2) is “not exist.” On the other hand, sincethe time period of the software update schedule for base-station number2 conflicts with the time period of the software update schedule forbase-station number 7, which is the one of the numbers of the basestations adjacent to the base station with base-station number 2, thedetermination result in the process (in step 12-2) is “exist.” When thedetermination result in the process (in step 12-2) is “not exist,” thetentatively determined date, day of the week, and time period areadopted, and a process of “specifying the date, day of the week, andtime period tentatively determined for the base station A in the process(in step 12-1) as determination” (in step 12-5) is carried out. Morespecifically, “tentative determination” is changed to “determination” inthe “tentative determination/determination” field. On the other hand, ifthe determination result in the process (in step 12-2) is “exist,” thenetwork management apparatus 250 carries out a process of “comparing thedegree of impact upon communication services for users between the basestations A and B” (in step 12-3).

If priority is given to the date, day of the week, and time periodrelated to the base station having the lower degree of impact in theprocess (in step 12-3), it is unavoidable for the base station havingthe higher degree of impact to select a date, day of the week, and timeperiod that will cause an even higher degree of impact. In short, it isexpected that the degree of impact will vary greatly among the basestations. To overcome this drawback, that is, to prevent the degree ofimpact from varying greatly among the base stations, the date and day ofthe week related to the base station having the higher degree of impactare selected with priority in subsequent processes.

When it is determined in the process (in step 12-3) that the degree ofimpact of the base station A is higher, the tentatively determined date,day of the week, and time period are adopted, and the process of“specifying the date, day of the week, and time period tentativelydetermined for the base station A in the process (in step 12-1) asdetermination” (in step 12-5) is carried. On the other hand, when it isdetermined in the process (in step 12-3) that the degree of impact ofthe base station B is higher or that the degree of impact is the samebetween the base station A and the base station B, a process of“excluding the date, day of the week, and time period tentativelydetermined for the base station A in the process (in step 12-1) from thecandidates and then re-making a “tentative determination” of a date, dayof the week, and time period with a minimum degree of impact uponcommunication services for users for the base station A” (in step 12-4)is carried out. Then, the process (in step 12-2) is carried out again.

The network management apparatus 250 repeats the processes (in steps12-1 to 12-5) for the base stations to be scheduled (process (in step12-6)) until all cells in the “tentative determination/determination”fields of FIG. 13 are set to “determination.” In this manner, the dateand time period of schedule for software update are established for allbase stations to be scheduled.

FIG. 13 shows the table 8 which reflects the state obtained while theprocess (in step 12-3) of FIG. 12 is being applied to the base-stationnumber 2. Referring to FIG. 13, the base station with base-stationnumber 7 is adjacent to the base station with base-station number 2, andfurthermore, the date, day of the week, and time period for softwareupdate of the base-station number 2 matches those of the base-stationnumber 7. In addition, the base-station number 7 has the higher degreeof impact upon communication services for users. In short, thedetermination result in the process (in step 12-2) is “exist” and thedetermination result in the process (in step 12-3) is “base station Bhas higher degree of impact.” In this case, the process of “excludingthe date, day of the week, and time period tentatively determined forsoftware update for the base-station number 2 from the candidates andre-making a tentative determination” (in step 12-4) is carried out.Referring to the service impact table 7 for base-station number 2 inFIG. 11B, “10:00-12:00 on September 2 (Monday)”, which was selectedbefore, is excluded, and therefore “13:00-15:00 on September 1 (Sunday)”can be “tentatively determined” as the date, day of the week, and timeperiod for software update for base-station number 2.

In the above-described embodiment, simultaneous software update both ina base station and an adjacent base station is not allowed. It is alsoacceptable to perform simultaneous software update in up to N adjacentbase stations. This can be achieved by changing the process (in step12-2) to a process of “determining whether there are N or more basestations adjacent to the base station A and having the samesoftware-update date, day of the week, and time period as thosetentatively determined.”

FIG. 14 shows the schedule adjustment table 8 obtained when theprocessing of FIG. 12 is completed. The date, day of the week, and timeperiod for software update for base-station number 2 have beenre-scheduled as described with reference to FIG. 13, and the basestation with base-station number 2 is scheduled for software update at13:00 to 15:00 on September 1 with a degree of impact upon communicationservices for users of 9.8. According to FIGS. 11A and 11B, the degree ofimpact upon communication services for users of base-station number 1 at13:00 to 15:00 on September 1 is 2.4, which is smaller than that ofbase-station number 2. If priority for software update is determinedsimply “in ascending order of the degree of impact upon communicationservices for users,” priority is given to base-station number 1 forsoftware update during the period 13:00 to 15:00 on September 1.Therefore, software update for the base-station number 2 is not carriedout during the period 13:00 to 15:00 on September 1. This causessoftware update for base-station number 2 to be carried out during atime period on a date with a higher degree of impact upon communicationservices for users. As described above, according to the method ofselecting a base station of this embodiment, the influence oncommunication services can be reduced.

In the above-described processes, the wireless base station having thelowest degree of impact is selected. Alternatively, wireless basestations having degrees of impact equal to or lower than a predeterminedthreshold may be selected. Furthermore, if the date and time periodscheduled for software update in the relevant base station matches thoseof an adjacent base station, a work date and a time period with the nextlowest degree of impact may be re-selected or another work date and timeperiod with a degree of impact equal to or lower than theabove-described threshold may be re-selected for one of the basestations. Alternatively, a work date and time period with a degree ofimpact equal to or lower than a second predetermined threshold (forexample, value larger than the above-described threshold) may bere-selected.

The present invention is applicable, for example, to the field ofindustry related to wireless communication systems including a pluralityof base stations and apparatuses.

1. A network management apparatus in a wireless communication network,which comprises a wireless base station for performing communicationbetween a wireless terminal and a wired communication network, and thenetwork management apparatus for managing a network, the networkmanagement apparatus comprising: a storage section stored in advancewith information indicating a number of calls of connection with thewireless terminal in the wireless base station in association with adate, a day of the week, and a time period; and a processing section forselecting a date and a time period when software is updated in thewireless base station based on said information stored in said storagesection, wherein the processing section: inputs a plurality of workdates and time periods when the software can possibly be updated in thewireless base station, obtains an n-week averages of the numbers ofconnection calls occurring during each input time period for each day ofthe week, based on the number of connection calls stored in the storagesection, where n is a predetermined integer, obtains, for each number ofdates in a month, an m-month averages of the numbers of connection callsoccurring during each input time period for each stored date on the samedate over the period from one to m months, based on the number ofconnection calls stored in the storage section, where m is apredetermined integer, calculates an average or a weighted average ofthe n-week average corresponding to each time period and the day of theweek of each input work date and the m-month average corresponding toeach time period and each input work date to obtain a degree of impactrepresenting an impact caused by software update upon a communicationservice, selects a work date and a time period with the minimum degreeof impact or with a degree of impact equal to or smaller than apredetermined threshold, and updates the software installed in thewireless base station during the selected time period on the selectedwork date.
 2. A network management apparatus according to claim 1,wherein the processing section transmits software and an update requestused for update according to the selected work date and time period tothe wireless base station and updates the software installed in thewireless base station to the transmitted software.
 3. A method ofselecting a wireless base station to update software installed in thewireless base station at a selected time period on a selected date, themethod comprising the steps of: inputting a plurality of work dates andtime periods when the software of the wireless base station can possiblybe updated; obtaining an n-week averages of the numbers of connectioncalls occurring during each of the input time periods for each day ofthe week, based on the number of calls of connection with a wirelessterminal in the wireless base station, corresponding to each date, dayof the week, and time period, where n is a predetermined integer;obtaining, for each number of dates in a month, an m-month averages ofthe numbers of connection calls occurring during each of the input timeperiods for each date on the same date over the period from one to mmonths, based on the number of connection calls, where m is apredetermined integer; calculating an average or a weighted average ofthe n-week average corresponding to each time period and the day of theweek of each input work date and the m-month average corresponding toeach time period and each input work date to obtain a degree of impactrepresenting an impact caused by software update upon a communicationservice; and selecting a work date and a time period having the minimumdegree of impact.